1. Field of the Invention
The invention relates to an erasing and cleaning apparatus, also called an erasing station, for cleaning cylindrical surfaces, in particular of printing form and blanket cylinders within printing presses with the aid of a cleaning cloth which is prepackaged in a cassette and can be moved by cleaning cloth transport means.
2. Description of the Prior Art
An erasing and cleaning apparatus of this type is known from U.S. Pat. No. 6,649,879.
The cleaning apparatus essentially comprises a clean cloth roll and a dirty cloth roll for accommodating a cleaning cloth which is impregnated with washing fluid and is pulled off the clean cloth roll onto the dirty cloth roll. Here, the cleaning cloth is always held under tensile stress by pressure means in the form of a wash roll. Furthermore, the cleaning apparatus is configured as a slide-in system and, in the installed state, is assigned to the cylindrical body which is configured, for example, as a blanket cylinder. The prepackaged cleaning cloth is moved into and out of contact with the blanket cylinder or an arbitrary cylinder of a printing unit by a positioning unit. A washing fluid supply system fixed to the machine is assigned to the cleaning apparatus. The clean cloth roll, the wash roll and the dirty cloth roll are mounted rotatably in two side parts arranged in parallel with one another. The wash roll has a surface which has an elastic coating and serves as a pressure element in order to press the cleaning cloth against the cylindrical body and simultaneously guide the cleaning cloth. The side parts of the slide-in system (that is to say, of the positioning unit) are connected to one another via a crossmember. The cleaning cloth is guided in as large a wrapping angle as possible from the clean cloth roll over the wash roll in the pulling direction of the dirty cloth roll. The cleaning cloth is wetted with a washing fluid. Drive is imparted to the dirty cloth roll via a shaft and gear wheel. The dirty cloth roll is operated intermittently and pulls the cleaning cloth from the clean cloth roll over the wash roll, which brings the cleaning cloth into contact with the cylindrical body to be cleaned, in the pulling direction and accommodates the cleaning cloth on a shaft.
It is possible to use the cassette universally in the printing press for every cylinder desired as a result of the fact that all the cleaning cloth transport means including the cleaning cloth are packaged in an independent cassette and a modular positioning unit can be arranged fixedly in the printing press, it being necessary to arrange only one positioning unit. It is not necessary to exchange the cleaning apparatus completely but only to remove the independent cassette from the positioning unit.
Hitherto, it has been somewhat cumbersome to change the cleaning cloth or exchange the cleaning cassette, to the extent that it cannot be performed when the printing press is running or with a paper web tensioned in the printing unit.